The present invention relates generally to systems for the injection of nitrous oxide into internal combustion engines, and is more particularly directed to a device and method for adjustably controlling the injection of nitrous oxide and supplemental fuel into such engines.
The output of an internal combustion engine is directly related to the density of air-fuel charge present when the combustion process takes place. As the density of the air-fuel charge increases, the horsepower and torque output increase as well. Some common methods used to increase the density of the air-fuel charge are to force air into the combustion chamber under pressure by the use of a turbocharger or supercharger.
Another method used is the introduction of nitrous oxide into the combustion chamber. Although nitrous oxide gas is non-flammable at room temperatures, when it super heats in the combustion chamber the nitrogen and oxygen molecules separate and make the oxygen available for the combustion process. Since air is only 21% oxygen by volume, the nitrous oxide gas provides a denser air charge within the engine. When additional fuel is added to this denser air charge, the power and torque output of the engine are increased. The amount of increase is proportional to the amount of nitrous oxide and fuel added to the engine. However, the maximum horsepower is ultimately limited by the mechanical limits of the engine.
Most conventional nitrous systems consist of: (1) a nitrous bottle; (2) a fuel control solenoid; (3) a nitrous oxide control solenoid; (4) a throttle switch; (5) a solenoid relay; and (6) flow control orifices. These systems are set up to activate the fuel and nitrous oxide control solenoids when the throttle reaches wide open. This is accomplished by the use of a switch mounted on the throttle body. When the solenoids are activated, nitrous oxide under high pressure enters the intake manifold or air stream of the engine. Simultaneously, the fuel solenoid is activated and fuel enters the intake manifold.
Some systems have an injection nozzle designed to mix the nitrous oxide and fuel together as they enter the intake manifold. The mixture is then ingested into the engine providing a much denser air-fuel mixture. The air-fuel mixture on conventional systems is determined by the orifice size in the fuel and nitrous oxide lines. The relationship between the fuel and nitrous orifice sizes must be refined until the proper air-fuel mixture is obtained. This process is time consuming and presents the possibility of engine damage during the tuning process if the air-fuel mixture becomes too lean. When there is too much nitrous oxide the air-fuel mixture becomes too lean and detonation can occur causing severe engine damage as the result of excessive combustion temperatures. Another disadvantage is the inability of the system to compensate for low bottle pressures. As the bottle pressure decreases the air-fuel mixture becomes excessively rich. This is a result or a lack of nitrous oxide in relationship to fuel. At some point the output of the engine is degraded as a result of this low bottle pressure condition.
Thus, the greatest challenge of nitrous oxide introduction into a combustion engine is the difficulty in maintaining a proper air-fuel ratio. Traditionally, nitrous oxide has only been introduced into the engine at wide open throttle. This is done because maximum power output of the engine is desired at wide open throttle and this provides only one condition in which auxiliary fuel enrichment is necessary. Since the nitrous oxide and auxiliary fuel flow is provided by a pair of fixed orifices in the delivery line, the air-fuel ratio is set for only one operating conditionxe2x80x94wide open throttle.
Although vehicle technology has advanced significantly over the recent years, there have been very few if any advancements in nitrous oxide injection systems. In fact, the addition of electronic fuel injection, onboard computer systems and the proliferation of system sensors have presented a challenge to companies offering nitrous oxide injection systems. Most of the available prior art systems still cater to vehicles that use carburetion as a method for fuel delivery. Companies offering nitrous oxide systems for more modern fuel-injected engines have found the only method to provide the necessary additional fuel is to increase the fuel pressure. This method of fuel enrichment applies abnormally high fuel pressure to the injectors, which can damage the injectors or cause fuel system leakage.
Accordingly, there is a substantial need in the art for improved devices and techniques to control the injection of nitrous oxide into engines that allow nitrous oxide to be injected at various throttle angles other than just wide open throttle; that eliminate the risk of engine damage; that do not cause inefficient burning of the air-fuel mixture associated with low bottle pressures, and that are adaptable to engines that use fuel injectors to deliver fuel to the engine.
The present invention specifically addresses and alleviates the above-mentioned deficiencies associated with the prior art. In this regard, the present invention comprises an improved injection valve apparatus for variably controlling the injection of nitrous oxide into a combustion engine, and methods for controlling and varying the amounts of nitrous oxide injected into a combustion engine based on existing vehicle performance conditions.
According to the preferred embodiment of the invention, a nitrous oxide injection apparatus is integrated into a vehicle""s existing systems to supply engine performance data to a computer management module, which is used to facilitate the controlled injection of nitrous oxide in varying amounts in response to changing engine conditions. The computer management module controls all aspects of data collection, analysis, and injection of nitrous oxide and corresponding supplemental fuel into the engine.
The computer management module interfaces with a vehicle""s existing systems through a wiring harness to receive engine performance data from the engine""s throttle position sensor, oxygen sensor, and ignition coil. The computer management module uses this data to calculate the amount of nitrous oxide to be injected, when to begin such injection, and whether additional fuel needs to be injected into the engine in response to the additional nitrous oxide injected. The wiring harness also connects to an LCD display preferably mounted to the dashboard of the vehicle, to provide the driver with system status information such as engine rpm, injector pulse width, air-fuel mixture, and throttle angle. The valve apparatus used for nitrous oxide injection provides linear control of nitrous oxide injection at high pressures of over 1000 psi.
Another preferred embodiment of the present invention allows the user to program the management module""s operation by selecting one of three operating modes, Linear, Drag or Timed mode. In drag mode, the system operates in the same way as conventional prior art nitrous oxide injection systems by delivering the programmed amount of nitrous oxide to the engine when the control module senses a wide open throttle angle. In linear mode, the user programs at what throttle angle to start introducing nitrous oxide. The control module then adds a proportionate amount of nitrous oxide in relation to the throttle angle; the higher the throttle angle, the greater the amount of nitrous oxide is supplied to the engine, up to the maximum amount the user has specified. This is expected to be the most popular mode of operation. In timed mode, the user programs at what throttle angle the nitrous oxide will be introduced and how much nitrous oxide will be added in terms of a percentage of valve orifice size. The user also enters a time delay or pause after the throttle angle is reached, and a nitrous oxide injection duration. This is ideal for turbo-charged engines because the nitrous oxide can be energized while the turbo reaches optimized boost levels and then deactivated after a certain amount of time. In all modes the user can program the maximum amount of nitrous that is introduced.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, various features of embodiments of the invention.